\documentclass{article}
\usepackage[T2A]{fontenc}
\usepackage[cp1251]{inputenc}
\usepackage[english,bulgarian]{babel}
\usepackage{pifont}
\usepackage{pstricks}
\newpsstyle{gridstyle}{subgriddiv=0,gridcolor=lightgray,griddots=10,gridlabels=6pt}
\usepackage{pst-pdf}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows,calc}

\begin{document}
\begin{pspicture}[showgrid=false](0,-0.2)(1,9.3)
% Define block styles
\tikzstyle{dia} = [diamond,shape aspect=2, draw,thick, fill=blue!20,text width=5em, text badly centered, node distance=2.5cm, inner sep=0pt,]
\tikzstyle{rec} = [rectangle, draw,thick, fill=blue!20,text width=14em, text centered, rounded corners, minimum height=2em]
\tikzstyle{line} = [draw, -latex']
\tikzstyle{del} = [draw=none,fill=none, inner sep=-8pt,outer sep=0pt, minimum size=2pt, node distance=6.3em,minimum height=0.1mm]

\pgfsetendarrow{\pgfarrowlargepointed{2.5pt}}


\begin{tikzpicture}[node distance = 1.5cm, auto]

Алгоритъм за обработка на инструкция

% Place nodes
    \node [dia, aspect=2] (A) {Прекъс-ване};
    \node [rec, right of=A, node distance=12.4em,text width=7.5em] (B) {Облсужване на прекъсването};
    \node [rec, below of=A, text width=9em, node distance=6em] (C) {Изтегляне на иснтрукцията};
    \node [rec, right of=C, node distance=12.4em, text width=7.5em] (D) {Декодиране на инструкцията};
    \node [rec, below of=D, text width=9em] (E) {Адресация на паметта};
    \node [rec, left of=E, text width=9em, node distance=12.5em] (F) {Изтегляне на операндите};
    \node [rec, below of=F, text width=9em] (G) {Изпълнение на операцията};
    \node [rec, below of=G, text width=9em] (H) {Запис на резултата};
    \node [del, above of=A, node distance=4em] (X) {};
    \node [del, above of=X, node distance=2ex] (T) {};

% Draw edges
    \path [line,thick] (A) -- node [near start,above] {да} (B);
    \path [line,thick] (A) -- node [near start, left] {не} (C);
    \path [line,thick] (C) -- (D);
    \path [line,thick] (D) -- (E);
    \path [line,thick] (E) -- (F);
    \path [line,thick] (F) -- (G);
    \path [line,thick] (G) -- (H);
    \path [line,thick] (T) -- (A);
    \path [line,thick] (B) |- (X);

    \draw [line,thick] ($ (H.south) + (0mm,0mm) $)-- ++(0,-.5) -- ++(-3,0)  |- ($ (X.west) + (0mm,0pt) $);
% -- ++ (0,9)
\end{tikzpicture}
\end{pspicture}

\end{document} 